I. Field of the Invention
This invention relates generally to a system for monitoring: a process. More particularly, this invention relates to such a system in which process data relating to a predetermined characteristic of the process is collected and stored in digital format and extracted based upon a pre-determined criterion for display.
II. Description of the Prior Art
Processes are known for the continuous production or handling of a product. Illustrative of such processes are those for the production or handling of continuous products, as for example polymeric films, paper webs, metallic webs, roll printing processes and the like. Other such processes include those for production or handling of discrete products such as sheet printing processes, packaging processes and the like.
A desired objective of these processes is that the product have certain pre-determined characteristics, as for example characteristics which insure that the product is of acceptable quality. A failure to detect and correct deviations from these pre-determined characteristics is an extreme disadvantage adversely affecting the economics of the process as for example because of lost production time, discarding of unacceptable product, and the like.
As a result, systems for inspecting and observing the product by continuous processes have been developed. See for example the systems described in U.S. Pat. Nos. 4,951,223; 4,814,869; 5,239,376; and the like. These systems usually involve the monitoring through use of one or more video cameras strategically placed along the production line, storage of video output on video tapes, means for shutting down production of the product in the event of deviations from pre-determined characteristics and playback of video tapes to determine the cause of the deviations so that corrections can be made in a timely fashion. These known monitoring systems suffer from one or more disadvantages which adversely affect their performance. For example, these prior processes are manual and require re-winding of the tape which results in down time of the system and long processing times. Moreover, tapes often degrade and it is difficult to access those portions of the tape containing relevant information or to make good copies. In these systems the tapes are not networked or tied together and the system cannot simultaneously recorded and played back. The system of this invention obviates one or more of these disadvantages.